Interpretive Summary: The numbers of natural enemies can be increased in crops by the addition of flowering plants, but these same plants may maintain pests. Scientists at the USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida investigated whether natural enemy-attractive flowers also attracted moths, a largely plant-feeding group of insects. Traps were baited with 12 species of plants and 5 of these attracted both parasitoids and moths. Different flowers attracted different kinds of moths, but in general larger moths were more likely to be captured in flower-baited traps. Attractive plants tended to have greater numbers of deeper flowers. The results emphasize that both the benefits and dangers of non-crop plants should be considered when they are to be added into agricultural environments.

Technical Abstract:
Flowering plants added to agricultural environments can provide food, shelter and alternative hosts for natural enemies and so increase crop yields. However, these same resources might be exploited by certain pests. Twelve species of plants, many of them Florida-native or established, known to attract parasitic Hymenoptera and Tachinidae and candidates for conservation biological control were examined for their attractiveness to Lepidoptera, a largely herbivorous order. Interception traps (Malaise traps) were erected along the margin of a field planted with either corn or rye (Zea mays L. and Secale cereale M. Bleb) depending on season and bordered by a forest dominated by water oak (Quercus nigra L.) and slash pine (Pinus elliottii Englem.). Under these traps were placed potted plants-with-flowers and controls consisting of plants-without-flowers and/or no plants. The various plant types were rotated among traps. Trapped Lepidoptera were counted, their wing lengths (size) measured and when possible identified to family and species. Five of the 12 plants-in-flower attracted greater numbers of Lepidoptera than their control(s) and attracted moths tended to be relatively large species. Flower depth, but not width, was correlated to attractiveness as was floral area, but not plant height. Finally the relative capacity of plants to attract both natural enemies and representative-herbivores was compared and it was suggested that such comparisons are useful in choosing non-crop plants for inclusion in agro-landscape modifications.